diff --git a/bacnet-stack/ports/at91sam7s/dlmstp.c b/bacnet-stack/ports/at91sam7s/dlmstp.c
index ca8a54c9..5a813e37 100644
--- a/bacnet-stack/ports/at91sam7s/dlmstp.c
+++ b/bacnet-stack/ports/at91sam7s/dlmstp.c
@@ -759,7 +759,8 @@ static bool MSTP_Master_Node_FSM(
                         break;
                     case FRAME_TYPE_TEST_REQUEST:
                         MSTP_Send_Frame(FRAME_TYPE_TEST_RESPONSE,
-                            SourceAddress, This_Station, NULL, 0);
+                            SourceAddress, This_Station,
+                            &InputBuffer[0], DataLength);
                         break;
                     case FRAME_TYPE_TEST_RESPONSE:
                     default:
diff --git a/bacnet-stack/ports/atmega168/dlmstp.c b/bacnet-stack/ports/atmega168/dlmstp.c
index c59560d6..15788f56 100644
--- a/bacnet-stack/ports/atmega168/dlmstp.c
+++ b/bacnet-stack/ports/atmega168/dlmstp.c
@@ -673,7 +673,8 @@ static bool MSTP_Master_Node_FSM(
                         break;
                     case FRAME_TYPE_TEST_REQUEST:
                         MSTP_Send_Frame(FRAME_TYPE_TEST_RESPONSE,
-                            SourceAddress, This_Station, NULL, 0);
+                            SourceAddress, This_Station,
+                            &InputBuffer[0], DataLength);
                         break;
                     case FRAME_TYPE_TEST_RESPONSE:
                     default:
diff --git a/bacnet-stack/ports/dos/dlmstp.c b/bacnet-stack/ports/dos/dlmstp.c
index cdaa38d5..68bebfe9 100644
--- a/bacnet-stack/ports/dos/dlmstp.c
+++ b/bacnet-stack/ports/dos/dlmstp.c
@@ -758,7 +758,8 @@ static bool MSTP_Master_Node_FSM(
                         break;
                     case FRAME_TYPE_TEST_REQUEST:
                         MSTP_Send_Frame(FRAME_TYPE_TEST_RESPONSE,
-                            SourceAddress, This_Station, NULL, 0);
+                            SourceAddress, This_Station,
+                            &InputBuffer[0], DataLength);
                         break;
                     case FRAME_TYPE_TEST_RESPONSE:
                     default:
diff --git a/bacnet-stack/ports/pic18f6720/mstp.c b/bacnet-stack/ports/pic18f6720/mstp.c
index 6cde0ad9..1509d15f 100644
--- a/bacnet-stack/ports/pic18f6720/mstp.c
+++ b/bacnet-stack/ports/pic18f6720/mstp.c
@@ -676,7 +676,9 @@ bool MSTP_Master_Node_FSM(
                             MSTP_Create_And_Send_Frame(mstp_port,
                                 FRAME_TYPE_TEST_RESPONSE,
                                 mstp_port->SourceAddress,
-                                mstp_port->This_Station, NULL, 0);
+                                mstp_port->This_Station,
+                                (uint8_t *) & mstp_port->InputBuffer[0],
+                                mstp_port->DataLength);
                             break;
                         case FRAME_TYPE_TEST_RESPONSE:
                         default:
diff --git a/bacnet-stack/ports/rtos32/mstp.c b/bacnet-stack/ports/rtos32/mstp.c
index 2b585e75..b9873b73 100644
--- a/bacnet-stack/ports/rtos32/mstp.c
+++ b/bacnet-stack/ports/rtos32/mstp.c
@@ -819,7 +819,9 @@ bool MSTP_Master_Node_FSM(
                             MSTP_Create_And_Send_Frame(mstp_port,
                                 FRAME_TYPE_TEST_RESPONSE,
                                 mstp_port->SourceAddress,
-                                mstp_port->This_Station, NULL, 0);
+                                mstp_port->This_Station,
+                                (uint8_t *) & mstp_port->InputBuffer[0],
+                                mstp_port->DataLength);
                             break;
                         case FRAME_TYPE_TEST_RESPONSE:
                         default:
diff --git a/bacnet-stack/src/mstp.c b/bacnet-stack/src/mstp.c
index 45e34fb9..e7bfc03c 100644
--- a/bacnet-stack/src/mstp.c
+++ b/bacnet-stack/src/mstp.c
@@ -632,7 +632,7 @@ MSTP_Put_Receive(mstp_port); break; case FRAME_TYPE_BACNET_DATA_EXPECTING_REPLY:
                     mstp_port->master_state =
                         MSTP_MASTER_STATE_ANSWER_DATA_REQUEST;}
 break; case FRAME_TYPE_TEST_REQUEST:
-MSTP_Create_And_Send_Frame(mstp_port, FRAME_TYPE_TEST_RESPONSE, mstp_port->SourceAddress, mstp_port->This_Station, NULL, 0); break; case FRAME_TYPE_TEST_RESPONSE:
+MSTP_Create_And_Send_Frame(mstp_port, FRAME_TYPE_TEST_RESPONSE, mstp_port->SourceAddress, mstp_port->This_Station, mstp_port->InputBuffer, mstp_port->DataLength); break; case FRAME_TYPE_TEST_RESPONSE:
 default:
                 break;}
             }